Ro-vibronic structure in the photoelectron spectra of H₂O, D₂O and HDO

Abstract

High resolution photoelectron spectra of H2O, D2O and HDO have been observed using He 584 Å excitation, and show partially resolved ro-vibronic structure. A comparison of the photoelectron spectra with optical spectra has been made, abd the 2 A 1 state of H2O+ is shown to have a linear conformation. A conflict between an earlier interpretation of the vibrational structure of the 2 B 2-1 A 1 spectrum and ab-initio calculations is resolved in terms of vibronic interaction between the 2 B 2 and 2 A 1 states, which can mix when the bond lengths become unequal.